Electrode support

ABSTRACT

An improved electrode support arrangement comprising a can adapted to surround an end of the electrode located exteriorly of a cell and conduct current to the electrode, a cylindrical member extending from the open end of the can and insulated from the can, a ceramic sleeve adapted to support an electrode located within the cylindrical member and supported on a lip carried on the cylindrical member and means to independently support the cylindrical member and the can.

United States Patent Inventors John C. Priscu;

Linden E. Snyder; Eldon R. Poulsen, all of Las Vegas, Nev. Appl. No. 810,603 Filed Mar. 26, 1969 Patented Sept. 21, 1971 Assignee Titanium Metals Corporation of America West Caldwell, NJ.

ELECTRODE SUPPORT 5 Claims, 2 Drawing Figs.

US. Cl 204/297 R, 204/286 Int. Cl C23b 5/70, 801k 3/04 Field of Search 204/ 286, 297

[56] References Cited UNITED STATES PATENTS 1,397,799 11/1921 Cutten 204/286 2,542,056 2/1951 Ravenscroft 204/286 2,648,631 8/1953 Carlisle 204/286 X 3,085,967 4/1963 Motock 204/297 X Primary Examiner-Howard S. Williams Assistant ExaminerD. R. Valentine Attorney-Webb, Burden, Robinson & Webb means to independently support the cylindrical member and the can.

PATENTEU SEP21 Ian 3.607708 sum 1 [1F 2 IN VE N TORS. John C. Prisca Linden E. Snyder 2%? R. Pnu/ en% BY@ 4% ,/A,/%

THE/R ATTORNEYS ELECTRODE SUPPORT This invention relates to an arrangement for supporting electrodes in an electrolytic cell, and more particularly to an arrangement for supporting the electrodes so that they are electrically insulated from the metal shell of the cell and so that the external ends are protected from contact with the ambient atmosphere.

Electrodes are utilized in fused salt electrolytic cells for producing titanium metal. Particularly, bottom entry anodes are used to obtain the proper electrode geometry and to permit insertion and removal of the cathode assembly without interference from electrical connections. The lower end of each anode is located externally of the cell, and a gastight closure must be maintained around the end to protect it from air and moisture. Additionally, each anode must be electrically insulated from the cell shell which is electrically connected with the negative pole of a current source. Furthermore, the external end of each anode must be cooled, and this creates a substantial temperature gradient between the portion of the anode located in the hot electrolyte and the cooled external portion of the anode. Since the anodes are made of graphite, it is necessary to provide a cushioning means to prevent breakage due to thermally induced changes in dimension. Anode breakage and short circuits result in inefficient cell operation due to increased maintenance expenses and increased cell downtime.

Our invention provides a novel arrangement for supporting individual anodes while providing a gastight seal around the external end of the anode and good electrical insulation between the anode and the cell shell. Additionally, the support arrangement of our invention has sufficient flexibility to absorb movement of the anode due to thermally induced changes in dimension without placing undue stress upon either the anode or the support structure. Another advantage of our arrangement is that it permits rapid replacement of damaged electrodes when necessary.

In the accompanying drawings, we have shown a preferred embodiment of our invention in which FIG. 1 is a schematic view of an electrolytic cell having a plurality of anodes with which our invention is used; and

FIG. 2 is a partial vertical section through a portion of the cell bottom showing the lower portion of an anode and a supporting arrangement according to our invention.

Referring to FIG. 1 of the drawings, the electrolytic cell includes a metal shell 1 having a refractory brick lining 2 containing a fused halide salt electrolyte 3. A plurality of anodes 4 extends upwardly through the cell bottom into electrolyte 3, and a cathode assembly 5 extends downwardly into the electrolyte from a cover 6 which is supported on cell top 7. A feed pipe extends through cover 6 into the cathode assembly so that gaseous titanium tetrachloride may be discharged within the cathode assembly. An electrical connection 9 connects cell top 7, cover 6 and cathode assembly 5 with the negative pole of a current source. The lower ends of the anodes are connected to the positive pole of a current source. The details of the cathode assembly, cover arrangement and feed pipe do not form any part of our invention and are not described in detail herein.

The support arrangement of our invention is shown in detail in FIG. 2 of the drawings. The end of each anode 4 extends through the cell bottom, and the external end is surrounded by a connector can 10 having its lower end 11 supported on an insulator 12 which is, in turn, supported on a bar 14. The connector can is made of metal, preferably copper, and is electrically connected with anode 4. In addition to providing an electrical connection between the anode and the current source, the can protects the lower portion of the external end of the anode from ambient air and moisture. A spiral cooling coil 21 surrounds the exterior of can 10, and water is continually circulated through the coil.

One end of bar 14 is attached to a turnbuckle 15 having a book 16 on its upper end for cooperation with a ring l7 welded to the metal cell shell. The other end of bar 14 is drilled, and a ringbolt 18 extends upwardly through the hole in the bar. Another ringbolt 19 is welded to shell 1 in alignment with bolt 18, and a coil spring 20 extends between the spaced rings of ringbolts 18 and 19 to provide a resilient mounting for bar 14. The tension of spring 20 may be adjusted by means of the turnbuckle to vary the force exerted on the anode by bar 4.

The upper end of can 10 is provided with an annular shoulder 22 having a horizontal portion 23 and a vertical portion 24. The lower end of a nozzle member 25 extends downwardly within the confines of shoulder 22 and is spaced from shoulder portions 23 and 24. Insulating and sealing members 26 and 27 are located respectively between the lower end of member 25 and shoulder portions 23 and 24. The upper end of member 25 is welded to an annular lip 28 which is supported from shell 1 by a plurality of studs 30 having nuts 31. The connection between shell 1 and lip 28 shown in FIG. 2 electrically insulates the lip and attached nozzle member 25 from the cathodic shell by means of an annular insulating member 32 and stud insulators 33 and 34. While insulating members 32, 33 and 34 are preferred, it should be understood that this insulation is not critical since lip 28 and nozzle member 25 are normally not in electrical contact with any metal surface other than shell 1.

A ceramic sleeve 35 surrounds a portion of the lower end of anode 4. Sleeve 35 has a rounded exterior shoulder 36 between its upper and lower ends, and this shoulder cooperates with the rounded inner periphery of lip 28 to support the sleeve adjacent the cell bottom. The upper inner edge of ceramic sleeve 35 is rounded at 37, and anode 4 is formed with a shoulder 4' having a rounded configuration corresponding with sleeve edge 37. When the anode is in place, it is completely supported on the rounded edge 37 of ceramic sleeve 35. The ceramic sleeve electrically insulates the anode from the cell shell 1.

It is important that the wall of can 10 terminate above the bottom of ceramic sleeve 35 since sublimates from the electrolyte within the cell may migrate or diffuse downwardly along anode 4 and condense in the cooled lower portion of the anode can which is surrounded by cooling coil 21. If connector can 10 terminated below the lower end of the ceramic sleeve, the sublimates could bridge the insulated gap between can 10 and member 25 and electrically connect the two. This is eliminated by extending the ceramic sleeve below the lower end of member 25.

A low melting point fusible metal alloy 38 is pumped through an inlet 39 into the space between the exterior of anode 4 and the lower portion of can 10. The low melting point fusible metal alloy provides an excellent electrical connection between can 10 and the end of the anode. An alloy which may be used for this purpose consists of about 52 percent bismuth, about 40 percent lead and about 8 cadmium. To further enhance the electrical contact between the can and the alloy, the inner surface of the can may be tinned.

A positive electrical connection is provided to each anode can by a connector 40 which is attached to an extension of the anode can bottom as shown in FIG. 2. A cable (not shown) fits within each connector 40, and a nut 41 is tightened to hold the cable in place. While cable connector 40 is shown, it should be understood that other types of connectors may be used.

Our invention has a number of important advantages which include a simple arrangement for supporting anodes which may be rapidly connected and disconnected to permit quick replacements of individual anodes. Additionally, our arrangement eliminates cooling the cell bottom since the anode cooling coil is part of the support structure. Our arrangement eliminates electrical short circuits and obviates damage to the anodes and the connectors due to thermally induced changes in dimension. Furthermore, an excellent gas seal is provided, and the lower end of the anode is protected from contact with the ambient atmosphere.

While our invention has been shown and described herein for use with an electrolytic cell having bottom entry anodes, it should be understood that the novel arrangement may be used in other environments to support both anodes and cathodes. Additionally, our invention is not limited to bottom entry electrodes, and it will be obvious to those skilled in the art that the sealing and support arrangement may be used with side and top entry electrodes.

While we have shown and described a preferred embodiment of the invention, it should be understood that the invention may be otherwise embodied within the scope of the appended claims.

What we claim is:

l. A support arrangement for an electrode, said arrangement including a current conducting connector can adapted to surround the end of an electrode, said can having means for connection with a current source, resilient mounting means for supporting said can, a hollow cylindrical member aligned with said can and adapted to surround a portion of an electrode and having an annular lip on the end removed from said can, said lip having a rounded inner periphery, electrical insu- 2. A support arrangement as set forth in claim 1 wherein the i inner surface of said connector can is partially tinned.

3. A support arrangement as set forth in claim 1 including cooling means surrounding the outer surface of said connector can.

4. A support arrangement as set forth in claim 1 including electrical insulating means between the exterior of the bottom of said connector can and said mounting means.

5. A support arrangement as set forth in claim 1 wherein the inner surface of said connector can is partially tinned and including cooling means surrounding the outer portion of said connector can and electrical insulating means between the exterior of the bottom of said connector can and said mounting means. 

2. A support arrangement as set forth in claim 1 wherein the inner surface of said connector can is partially tinned.
 3. A support arrangement as set forth in claim 1 including cooling means surrounding the outer surface of said connector can.
 4. A support arrangement as set forth in claim 1 including electrical insulating means between the exterior of the bottom of said connector can and said mounting means.
 5. A support arrangement as set forth in claim 1 wherein the inner surface of said connector can is partially tinned and including cooling means surrounding the outer portion of said connector can and electrical insulating means between the exterior of the bottom of said connector can and said mounting means. 